1. Field of the Invention
The present invention relates to a permanent magnet type rotating electrical machine.
2. Description of the Related Art
A permanent magnet type rotating electrical machine, in particular, a permanent magnet type rotating electrical machine used for vehicle driving, is required to have a smaller size and a higher output, including an inverter that serves as a control circuit for the rotating electrical machine. Especially, there is a demand for a permanent magnet type rotating electrical machine that is capable of outputting large torque in a low-speed rotation range and maintaining a high output in a high-speed rotation range as well. To meet such a demand, many of permanent magnet type rotating electrical machines have hitherto been practiced as the embedded permanent magnet type provided with auxiliary salient poles, which can not only perform field weakening control, but also utilize reluctance torque in the high-speed rotation range. For example, JP,A 10-126985 (Patent Document 1) discloses the structure of one embedded permanent magnet type rotating electrical machine.
Other related structures of rotating electrical machines are disclosed in, e.g., JP,A 2005-6484 (Patent Document 2), JP,A 2002-354726 (Patent Document 3), JP,U 7-11859 (Patent Document 4), and Japanese Patent No. 3598887 (Patent Document 5).
In permanent magnet type rotating electrical machines, it is demanded to increase an output even just a small percentage, e.g., 1%, under condition of limited supply of power in vehicles. A permanent magnet type rotating electrical machine generates an electromotive force by receiving current and voltage supplied from an inverter as a control circuit. To obtain a higher output in the permanent magnet type rotating electrical machine, therefore, the waveform of voltage induced by the permanent magnet type rotating electrical machine has to be adjusted, taking into account the mutual relationships among components including the inverter as well. Known techniques for adjusting the waveform of voltage induced by the permanent magnet type rotating electrical machine are disclosed in, e.g., JP,A 2001-112202 (Patent Document 6) and JP,A 2002-78260 (Patent Document 7).